Essential Oil and Smoke Components of Artemisia absinthium and Hagenia abyssinica

Hagenia abyssinica and Artemisia absinthium are widely distributed tree species in Ethiopia and known for their traditional medicinal uses. The present study was conducted to determine the essential oil and smoke constituents of H. abyssinica and A. absinthium leaves using GC-MS. The main components of the A. absinthium essential oil were valencene (5.48%), bornyl acetate (5.15%), and trans-cinnamic acid (4.34%). 2-Bornanone (18.54%), o-cymene (12.80%), and nerolidol (7.04%) were the dominant components of the MeOH fraction of the smoke derived from the leaves of A. absinthium, while 2-propenoic acid butyl ester (46.49%), heptadecane (10.66%), and 9-octylheptadecane (7.78%) were the major components of the n-hexane fraction. The main components of the H. abyssinica essential oil were cis-davanone (14.73%), Aristolediene (9.31%), and cryptone (6.50%). β-Myrcene (12.59%), neophytadiene (11.54%), and limonene (11.27%) were the dominant components of the MeOH fraction of the smoke derived from the leaves of H. abyssinica. 1,3,5,7-Cyclooctatetraene (33.58%), prehnitene (7.01%), and heptadecane (5.46%) were the dominant components of the n-hexane fraction of the smoke derived from the leaves of H. abyssinica. The smoke components of A. absinthium and H. abyssinica were reported here for the first time.


Introduction
Artemisia absinthium locally known as "ariti" is a perennial odorous herb which is widespread in Ethiopia.A. absinthium exhibited antispasmodic and antioxidant properties.It is used for treatment of cough and malaria [1,2].Different natural products were isolated from the roots of A. absinthium [3].The chemical composition and biological activity of the essential oil from this plant were also reported several times [4][5][6][7][8].
Although A. absinthium and H. abyssinica are widely used for treatment of different diseases and as incense plants in Ethiopia, the chemical composition of the smoke from these plants was not reported before.This study focuses on the extraction of essential oil from the leaves of A. absinthium and H. abyssinica using hydrodistillation and collection of medicinal smoke from the leaves of A. absinthium and H. abyssinica using n-hexane and methanol and comparison of their constituents.

Experimental
2.1.General Experimental Procedure.All the chemicals, reagents, and solvents were analytical/HPLC grade.The essential oil and smoke obtained from the leaves of A. absinthium and H. abyssinica were analyzed by using an Agilent Technology 7820A GC system coupled with an Agilent Technology 5977E MSD following the procedure described by Sisay et al. [15].A DB-1701 column (30 × 0 25 μm) was used for chromatographic separation with helium (99.999%) as carrier gas at constant flow rate (0.97989 ml/min). 1 μl of the sample was injected with a splitless mode into the inlet heated to 275 °C.The initial column temperature was 60 °C and hold time of 2 min with a total run time of 29.33 min.The different components of the essential oil and smoke were identified through NIST 2014 library search and retention index (RI) calculation.

Extraction of Essential Oil from the Leaves of Artemisia absinthium and Hagenia abyssinica by Hydrodistillation.
The essential oil from the leaves of A. absinthium and H. abyssinica was extracted following the procedure described by Costa et al. [16].The dried and ground leaves of A. absinthium and H. abyssinica each (100.0 g) were placed in a distillation flask containing distilled water (500.0ml).The distillation flask was attached to a Clevenger apparatus and a condenser which was then heated to boiling.The essential oil was separated from aqueous layer and analyzed by GC-MS.
2.4.Collection of the Smoke from the Leaves of Artemisia absinthium and Hagenia abyssinica.The smoke from the leaves of A. absinthium and H. abyssinica was collected following the procedure described by Sisay et al. [15].Dried and powdered leaves of A. absinthium and H. abyssinica each (100.0 g) were burned using an electrical stove, and the smoke was collected using an inverted funnel fitted with a rubber tube which was allowed to pass thorough a suction   3 International Journal of Food Science flask (250.0 ml) containing MeOH (100.0 ml) which in turn was connected to another (250.0ml) suction flask that contained n-hexane (100.0 ml).The side arm of the n-hexanecontaining flask was attached to a water aspirator.The extracts were dried using anh.Na 2 SO 4 , filtered and concentrated under reduced pressure to yield MeOH (1.50 g) and nhexane (250.15mg) residues for the leaves of A. absinthium and MeOH (1.25 g) and n-hexane (150.50 mg) residues for the leaves of H. abyssinica, which were then analyzed by GC-MS.Retention index (RI) was calculated for the different components in the essential oil and smoke.For retention index calculation, a mixture of n-alkanes (C7-C23) was injected and analyzed using the same experimental condition as that of the essential oil analysis.The retention indices of the different components were then calculated according to the van den Dool and Kratz relationship [17].
27 compounds, 9 from the MeOH-soluble portion and 18 from the n-hexane fraction, of the smoke obtained from the leaves of A. absinthium were identified (Figures 3 and 4).2-Bornanone (18.54%), o-cymene (12.80%), and nerolidol (7.04%) were the dominant components of MeOH fraction of the smoke derived from the leaves of A. absinthium (Table 2).In addition, 2-propenoic acid butyl ester (46.49%), heptadecane (10.66%), and 9-octylheptadecane (7.78%) were the dominant components of n-hexane fraction of the smoke derived from the leaves of A. absinthium (Table 3).The chemical composition of the smoke obtained from burning the leaves of A. absinthium was reported here for the first time.

GC-MS Characterization of the Essential Oil and Smoke
Derived from the Leaves of Hagenia abyssinica.1.25 ml of essential oil was collected from the leaves of H. abyssinica (1.07 g, 1.07%), and MeOH (1.25 g) and n-hexane (150.50 mg) solvent-trapped residues were obtained from the leaves of H. abyssinica.The main components of H. abyssinica essential oil were cis-davanone (14.73%),Aristolediene (9.31%), and cryptone (6.50%); these together constituted 30.54% of the extracted essential oil (Figure 5 and Table 4).
The essential oil from the leaves of A. absinthium yielded a characteristic blue oil which is reported to be due to an    8 International Journal of Food Science

Conclusion
In this work, the essential oil from the leaves of A. absinthium and H. abyssinica together with the smoke obtained by burning the leaves of A. absinthium and H. abyssinica was analyzed by GC-MS.Eighteen and eleven compounds were identified from the essential oil of A. absinthium and H. abyssinica, respectively.The smoke from the leaves of A. absinthium yielded 27 compounds, 9 from the MeOH-soluble portion and 18 from the n-hexane fraction.In addition, 39 compounds, 15 from the MeOHsoluble fraction and 24 from the n-hexane fraction, of the smoke obtained from the leaves of H. abyssinica were identified.

Table 1 :
Composition of A. absinthium essential oil.
PK = peak number; RT = retention time; Area% = area percentage; Q = quality; RI = retention index.5 International Journal of Food Science

Table 4 :
Composition of H. abyssinica essential oil.

Table 6 :
[19]osition H. abyssinica smoke (n-hexane fraction).Bornyl acetate, trans-ethyl cinnamate, and davanone were found to be the common components of the essential oil from the leaves of A. absinthium and the MeOH-soluble fraction obtained by burning the leaves of A. absinthium.Oxidation products were also observed in the MeOH-soluble fraction such as 2-bornanone which is the oxidation product of the essential oil component borneol.Davanone was the common component in the essential oil from the leaves of A. absinthium as well as the MeOH-and hexane-soluble fractions obtained by burning the leaves of A. absinthium.Davanone was previously reported to be the major constituent of the essential oil of the leaves of A. absinthium[4].The chemical constituents of essential oils from the Artemisia genus have been extensively studied around the world.Camphor, chamazulene, β-myrcene, β-pinene, trans-sabinyl acetate, and β-thujone were reported to be the major constituents of A. absinthium different parts from different geographic locations using various extraction methods[18].The essential oil from the leaves of H. abyssinica was found to be dominated by terpenes (30.79%) and aromatic alcohols (8.85%).Terpenes (41.09%) and long chain hydrocarbons (63.04%) were the predominant constituents of the MeOH-and nhexane-soluble fractions obtained by burning the leaves of H. abyssinica, respectively.Several previous studies suggested that the main chemical constituents of H. abyssinica are phloroglucinol derivatives, phenols, saponins, flavonoids, anthraquinones, terpenoids, alkaloids, steroids, glycosides, and tannins[19].

Table 6 :
Continued.= peak number; RT = retention time; Area% = area percentage; Q = quality; RI = retention index.11 International Journal of Food Science PK